INDUSTRIAL WOOD CHIPPER KNIFE AND METHOD FOR MANUFACTURING AN INDUSTRIAL WOOD CHIPPER KNIFE

Abstract

A chipper has a knife clamped between a clamp and a counter knife that sits on a holder. The knife, damp, and counter knife are collectively positioned in a machined area formed in a holder that is in turn within a larger recess formed in a chipping disk or chipping drum.

A first fastener secures the knife holder to the chipping disk, a second fastener secures the clamp to the knife holder, and a third fastener secures the counter knife lo the knife holder. The knife comprises a ridge which is formed by the termination in two straight lines which form a triangle shape on the bottom of the knife. These straight lines reduce the manufacturing cost of the knife and provide support for the knife to locate. The knife is also manufactured without 100% grinding of all services, which is unique in that this reduces manufacturing costs dramatically.

Claims

1. An industrial wood chipper knife with an elongated axis terminating in two opposing parallel cutting edges, the two cutting edges each being straight in part and being separated by a ridge, where-in the ridge comprises two symmetrical straight ridge edges on either side of a central point which form an isosceles triangle where-in these ridge edges are defined by being straight and not concave or round.

2. The industrial wood chipper knife according to claim 1 the angle between a cutting edge and a ridge edge is greater than 90 degrees.

3. The industrial wood chipper knife according to claim 1 further comprising a top clamping feature that includes two distinct angles on each side where the clamp holds the knife.

4. The industrial wood chipper knife according to claim 1 further comprising two identical indention lines on each of the cutting edges, which indentation lines are parallel and terminate the ridge.

5. A method for manufacturing an industrial wood chipper knife, where in the method comprises: a) Supplying raw material made of steel in round or square shape; b) Hot rolling that raw material through shaped rolls to create the general form of the knife; c) Cold drawing, or extruding, the steel through multiple dies to create a final shape, where the final shape is a wood chipper knife comprising an elongated axis terminating in two opposing cutting edges, each with a parallel straight lines separated by a ridge in the middle of the bottom side, where in the ridge on the bottom of the knife comprises two symmetrical straight lines on either side which form a triangle where in these lines are specifically defined by being straight and not being concave or round; and d) sharpening the area near the edges.

Description

DESCRIPTION OF THE FIGURES

[0012] FIG. 1 shows a reversible chipper knife according to an embodiment of the invention.

[0013] FIG. 2 shows the reference lines used to define the position and description of the elements of a reversible chipper knife according to an embodiment of the invention.

[0014] FIG. 3 shows an illustration of reversible chipper knife according to the prior art.

[0015] FIG. 4 shows an illustration of another reversible chipper knife according to the prior art.

[0016] FIG. 5 shows the restricted grinding, or machining area, that is part of invention for the method for manufacturing a reversible chipper knife according to an embodiment of the invention.

[0017] FIG. 6 shows one iteration of the reversible chipper knife without the indentions on the bottom of the knife, according to an embodiment of the invention.

[0018] FIG. 7 shows the first iteration of the reversible chipper knife includes the indentions on the bottom, according to an embodiment of the invention.

[0019] FIG. 8 shows a knife with a single ridge on the bottom of the knife, according to the prior art.

[0020] FIG. 9 shows the the grinding area after heat treatment with the manufactured method, according to an embodiment of the invention.

[0021] FIG. 10 shows the grinding area of the manufacturing method, according to an embodiment of the invention.

[0022] FIG. 11 shows another view of the the limited grinding area of the knife after heat treatment.

DETAILED DESCRIPTION OF THE INVENTION

[0023] The knife and manufacturing process of the present invention is an improvement on existing designs by optimizing the size of the knife to eliminate twisting and bending associated with patent U.S. Pat. No. 8,082.958 and the leverage action that causes 49.918 to lose stability, while also drastically reducing the manufacturing cost by eliminating the need for expensive form grinders.

[0024] The current invention solves the problem of twisting and bending of the knife by utilizing a multy angle clamping zone that is narrower than patent U.S. Pat. No. 8.082.958 yet provides equal or greater clamping force. The invention provides more contact on the bottom of the knife, which allows the clamping area to be narrower and add thickness to the knife. This added thickness prevents the knife from bending or twisting during heavy operation.

[0025] The leverage action caused by the prior art in 49.918, which g increases the force on the knife and requires a large clamp to hold the knife in place, is not present with the new invention which utilizes an optimum sized knife, approx., 40% smaller than 49.918e. The indexing features on 49.918, which lead to a concave and aggressive ridge that creates small pin chips, is eliminated with the invention. The invention solves the problem of increasing pin chips with an aggressive ridge by optimizing this transition angle, which is a flat line and is over 90 degrees from the line on the bottom of the knife. This permits the wood chips to continue their natural path towards the back of the chipper disc and reduces the impact on the high quality chips.

[0026] The knife comprises a top clamping zone (7) in FIG. 1, which constitutes two symmetrical areas defined by reference line 2 from FIG. 2 with each side containing two distinct angles (1) and ( 2), which are used to contact tho clamp and fix the knife in place with much more force than traditional prior art. These angles culminate in a round point (12) in the center of the clamping zone (7). This round point (12) is located on reference line 2 from FIG. 2 in the center of the knife. This top clamping zone (7) is contacted by the clamp so when the clamp bolts the knife into place there is contact. The round point (12) is not contacted by the clamp as the clamp holds the knife with force only in points (1) and (2) on each side.

[0027] This contact zone (7) terminates on each side in a flat surface (3) on each side of the contact zone. After these flat surfaces (3), a bevel lines on the knife (9) begin, which is terminated in two opposed cutting edges (4).

[0028] The bottom of the knife is defined by two parallel lines (8) on each side of She reference line 2 defined in FIG. 2, which terminate in the opposed cutting edges (4). These parallel lines define reference line 1. The knife has two iterations, one with indention lines (6), which are parallel to lines (8) and do not have contact with the counterknife and do not locate the knife in place. These indention lines end in a respective round point (11) and then continue to form the chip deflecting ridge on the knife with straight lines (5), terminating in a rounded crest point (10) which lies on the same reference line 2 as point (12). The other iteration does not have the indention lines (6).

[0029] The deflector ridge on this knife is defined by the two straight lines (5), which form a triangle at point (10). The angle between (5) and parallel lines (8) must be greater than 90 degrees (see FIGS. 6 and 7)

[0030] Within the wood chipping process, the objective is to cut the chip and then provide the optimal transition for the chip to pass through the disc bottom of the knife (6, 8. 11, 5), seen on FIG. 1, in order to maintain the proper chip thickness. The ridge on the bottom of the knife of the present invention is unique in that it has a flat straight portion (5) where it contacts the counterknife and the angle with respect to the linear line on the bottom of the knife is over 90 degrees. This flat portion reduces the manufacturing cost of the knife and counterknife, while also providing an optimal wood chip transition to maintain the quality of the wood chips. This is an improvement over the aggressive ridge with guiding services in patent 49.918. One iteration of the invention (see FIG. 5) is the indentions (6) with a flat surface on each side of the ridge. These indentions (6) further reduce material cost while also pushing the force of the clamp closer to the edges of the knife). This increases the stability of the knife while also reducing the material used to manufacture the knife. These indentions are unique from patent 49.918 because the indentions in patent 49.918 are used to guide and locate the knife with the counterknife (FIG. 3) and are rounded with a minimum point in the center. The indentions in this invention are not used to guide or locate the knife and there is no contact with the supporting counterknife below it. They provide added knife stability by spreading the clamping force closer to the tip of the knife.

[0031] The invention also claims a manufacturing process that uses a near-net profile for the raw material, yet this near-net profile shape is unique in that it already achieves the final dimensions of the knife and only has added material near the bevel of the knife (FIG. 9). The first step in the manufacturing process is hot rolling the steel through rolls, which creates the general shape, followed by a cold extrusion, also known as cold drawing, through multiple dies until the final shape is achieved. The above process has been used for many years in the manufacturing of knives; however, the knives are then further machined on all of the surfaces alter the heat treatment of the steel shape. This new invention achieves 80% of the final shape of the knife in the cold extrusion process and the only machining process remaining is sharpening the edges (see FIG. 5 and FIG. 9). After the cold extrusion of the knife, the knives are cut to length and then heat treated to the correct hardness. Alter heat treatment the knife is cleaned and the edges are sharpened (FIG. 9, 10, 11). This process is unique in that it eliminates the majority of the cost associated with finish grinding, which is the most expensive cost component of reversible, or indexable knife manufacturing.